(Richmond, IN)--There’s been no official explanation on the source of a loud boom that rocked Richmond Monday night. It happened at around 10 o’clock Monday night. Residents across the east side, in Meadow Park and in Oak Park heard it. A resident of South 19th said it shook her house. It was even heard in New Paris. There was speculation that it was a transformer, but there were no power outages. There was also a theory that it was trains coupling. There was no official response to the boom from police or fire last night.